Mind-wandering is not only a common activity, present in roughly 50% of our awake life, but is also associated with lower levels of happiness (Killingsworth & Gilbert, 2010, Science 330(6006):932). Moreover, mind-wandering is known to correlate with neural activity in a network of brain areas that support self-referential processing, known as the Default Mode Network (DMN) (Mason et al., 2007, Science 315(5810):393; Raichle et al., 2001, Proc. Natl. Acad. Sci. USA 98(2):676; Christoff et al., 2009, Proc. Natl. Acad. Sci. USA 106(21):8719-8724; Simpson et al., 2001, Proc. Natl. Acad. Sci. USA. 98(2):688-693; Buckner R L, Andrews-Hanna J R, & Schacter D L (2008) The brain's default network: Anatomy, function, and relevance to disease, The year in cognitive neuroscience 2008, eds Kingstone A & Miller M B (Blackwell Publishing, Malden, Mass.), pp 1-38; Andrews-Hanna et al., 2010, Neuron 65(4):550-562). This network has been associated with processes ranging from attentional lapses to anxiety, as well as to clinical disorders such as Attention Deficit Hyperactivity Disorder (ADHD) and Alzheimer's Disease (Buckner R L, Andrews-Hanna J R, & Schacter D L (2008) The brain's default network: Anatomy, function, and relevance to disease, The year in cognitive neuroscience 2008, eds Kingstone A & Miller M B (Blackwell Publishing, Malden, Mass.), pp 1-38; Weissman et al., 2006, Nat. Neurosci. 9(7):971-978; Castellanos et al., 2008, Biol. Psychiatry 63(3):332-337).
One potential way to reduce DMN activity is through the practice of mindfulness-based meditation. Mindfulness, a core element of diverse forms of meditation, is thought to include two complementary components: 1) maintaining attention on the immediate experience, and 2) maintaining an attitude of acceptance toward this experience (Bishop et al., 2004, Clin. Psychol 11(3):230-241). Specific types of mindfulness meditation have been taught in a standardized fashion for decades as a mainstay of mindfulness training in community and clinical settings (e.g., through traditional teacher- or retreat-led mindfulness meditation practice, Mindfulness Based Stress Reduction, Mindfulness Based Cognitive Therapy and Mindfulness Based Relapse Prevention) (Gunaratana H (2002), Mindfulness in Plain English (Wisdom Publications, Somerville, Mass.); Chiesa, 2010, J. Altern. Complement. Med. 16(1):37-46; Kabat-Zinn et al., 1985, J Behav. Med. 8(2):163-190; Teasdale et al., 2010, J. Consult. Clin. Psychol. 68(4):615-623; Bowen et al., 2009, Substance Abuse 30(4):295-305).
Three standard and commonly used meditation practices are: Concentration, Loving-kindness, and Choiceless Awareness. Through focused attention on a single object of awareness (typically the breath), Concentration meditation is intended to help individuals retrain their minds from habitually engaging in self-related pre-occupations (such as thinking about the past or future, or reacting to stressful stimuli) to more present moment awareness (Gunaratana H (2002), Mindfulness in Plain English (Wisdom Publications, Somerville, Mass.)). Loving-kindness meditation is hypothesized to foster acceptance, both of oneself and others, as well as to increase concentration. It is practiced through directed well-wishing, typically by repetition of phrases such as “may [I/someone else] be happy” (Gunaratana H (2002), Mindfulness in Plain English (Wisdom Publications, Somerville, Mass.)). Choiceless Awareness is hypothesized to broaden the scope of mindfulness to all aspects of experience, whether during formal meditation practice or everyday life, via directly attending to whatever arises in one's conscious field of awareness at any moment (Gunaratana H (2002), Mindfulness in Plain English (Wisdom Publications, Somerville, Mass.); Lutz et al., 2008, Trends in Cognitive Sciences 12(4):163-169). During such training, meditators learn to clearly identify when self-related thoughts, emotions and body sensations are occurring, and to differentiate identification of these from identifying with them (e.g. awareness that anger is present vs. “I am angry”). That is, meditators practice noticing when they are identifying with an object, and when this occurs, to “let go” and bring their attention back to the present moment. Across these practices, one common aim is to reverse the habit of mind-wandering, which has been defined as “thinking about something other than what [one is] currently doing” (Killingsworth & Gilbert, 2010, Science 330(6006):932). In other words, the meditator's task is to remain aware from moment to moment, and self-identification is included in the off-task category of mind-wandering. Importantly, this information processing task, common to all three of these meditation techniques, is a training of attention away from self-reference and mind-wandering—and potentially away from default-mode processing.
Clinically, mindfulness training has shown benefit for the treatment of pain (Kabat-Zinn et al., 1985, J Behav. Med. 8(2):163-190), substance use disorders (Bowen et al., 2009, Substance Abuse 30(4):295-305; Brewer et al., 2009, Substance Abuse 30(4):306-317), anxiety disorders (Goldin et al., 2009, J. Cognitive Psychotherapy 23(3):242-257), and depression (Teasdale et al., 2010, J. Consult. Clin. Psychol. 68(4):615-623), while also helping to increase psychological well-being in non-clinical populations (Kingston et al., 2007, J Psychosom. Res. 62(3):297-300). These outcomes have been associated with changes in basic psychological processes such as improved attentional focus (Jha et al., 2007, Cogn Affect Behav Neurosci 7(2):109-119; Lutz et al., 2009, J Neurosci 29(42):13418-13427), improved cognitive flexibility (Moore & Malinowski, 2009, Conscious Cogn 18(1):176-186), reduced affective reactivity (Farb et al., 2010, Emotion 10(1):25-33; Goldin & Gross, 2010, Emotion 10(1):83-91), and modification or shifts away from distorted or exaggerated view of oneself (Goldin et al., 2009, J. Cognitive Psychotherapy 23(3):242-257; Farb et al., 2007, Soc Cogn Affect Neurosci 2(4):313-322). However, direct links between the meditative practices that are part of mindfulness training and changes in neurobiology remain elusive. Investigation of the brain activation patterns during specific meditation practices may help to identify potential neural mechanisms of mindfulness training.
Previous studies have examined individuals using meditation techniques from different traditions (e.g. Tibetan Buddhism, Zen Buddhism, Vipassana, Mindfulness-Based Stress Reduction, etc.), and employed a wide variety of experimental methods ranging from performance of different types of meditation, to introduction of emotionally-charged sounds during meditation, to assessment of functional connectivity (Lutz et al., 2008, Trends in Cognitive Sciences 12(4):163-169; Manna et al., 2010, Brain Res Bull 82(1-2):46-56; Ives-Deliperi et al., 2011, Soc Neurosci. 6(3):231-42; Brefczynski-Lewis et al., 2007, Proc Natl Acad Sci USA 104(27):11483-11488; Holzel et al., 2007, Neurosci. Lett. 421(1):16-21). However, given the methodological differences and in some cases, difficulty in finding appropriately-matched controls, no consensus has emerged as to what the neural mechanisms of meditation are, or how they may underlie the behavioral changes that have been observed after mindfulness training.
Finding the connection between the mind and the brain has fascinated neuroscientists for centuries. A rich and complex history has emerged around the study of first-person subjective reporting in pursuit of understanding human experience. Recent technological advances have increasingly refined the objective measurement of neuronal processes that are present during human experience. However, links between these third-person measurements and first-person subjective reports have not been established due, at least in part, to several methodological challenges that are inherent in these methodologies. One of the main challenges in gathering subjective data is that self-reports can be inaccurate or biased (Nisbett & Wilson, 1977, Psychological Review 84(3):231). Another difficulty is in capturing and characterizing subjective experiences that may regularly reside outside of the conscious attention, such as the visual experience of seeing a color, or the auditory experience of listening to music. Additionally, people vary greatly in their ability to observe and report upon their experiences due to variability in the degree of their awareness of the contents of their own thoughts (Christoff, et al., 2009, Proc Natl Acad Sci USA 106(21):8719-8724) as well as fluctuations in their attention levels (Tononi & Koch, 2008, Ann N Y Acad Sci 1124(1):239-261). Furthermore, the act of generating a contemporaneous introspective report about an experience may serve to modify the experience itself (Lutz & Thompson, 2003, J. Consciousness Studies, 10(9-10): 31-52). For example, during introspective states such as meditation, the act of self-reflection pulls the individual out of the meditative state.
Relating subjective experiences and observed measurements or data seems simple enough in theory—gather a subjective first-person report about an experience as contemporaneously with the experience as possible, and gather third-person, objective data about behavior and brain processes simultaneously with the experience, then formulate concepts of principles of mechanisms that might underlie the experience based upon possible correlations between the two (Chalmers D J (2000), What is a neural correlate of consciousness? In: Neural Correlates of Consciousness: Empirical and Conceptual Questions, Metzinger T, ed., pp. 17-40. MIT Press: Cambridge, Mass.). This study design has proven to be more difficult in practice than it is in theory, as noted above. A number of recent studies have devised strategies for solving this problem. For example, in their investigation of the neural basis of mind-wandering, Christoff and colleagues used experience sampling during fMRI scanning, where, during a sustained attention task, subjects were intermittently asked to report where their attention was focused and whether they were on- or off-task preceding the query (Christoff, et al., 2009, Proc Natl Acad Sci USA 106(21):8719-8724). In this study, when subjects reported being off-task, they showed activation in the brain's default mode network (DMN), a network that reliably demonstrates involvement in both mind-wandering, and self-referential processing (Kelley, et al., 2002, J Cogn Neurosci 14(5):785-794; Northoff, et al., 2006, NeuroImage 31(1):440-457; Weissman, et al., 2006, Nat Neurosci 9(7):971-978; Mason, et al., 2007, Science 315(5810):393). Importantly, DMN activation was strongest when subjects were unaware of their own mind-wandering. Similarly, Hasenkamp and colleagues designed a method in which subjective information was simultaneously collected alongside fMRI data (Hasenkamp, et al., 2012, Neuroimage 59(1):750-60). They instructed meditators to meditate in the fMRI scanner and to press a button whenever they realized their minds had wandered. They differentially analyzed periods before and after the button press to determine brain activation patterns that were activated during presumptively different cognitive states. They, too, found that DMN activation correlated with mind-wandering, and that salience/attention network regions (e.g., dorsal anterior cingulate) were activated during awareness of mind-wandering. The objectivity of these studies is much improved over the use of retrospective recall alone. Nevertheless, a query or button press pulls individuals out of their current mind-state and the amount of subjective information that can be gathered during these types of experiments is somewhat limited, potentially leading to reverse inference of the cognitive processes that may actually be active at the times of the probes (Poldrack, 2006, Trends in Cognitive Sciences 10(2):59-63; Christoff, et al., 2009, Proc Natl Acad Sci USA 106(21):8719-8724). Thus, methods are still needed to refine the improved resolution afforded by using fMRI and self-report together, and to include more detailed subjective accounts in a less disruptive manner.
Another recent advance in the field of neuroimaging has been the development of real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback. This technique retains the advantage of collecting objective sampling data contemporaneously with the event, as in the studies highlighted above, but has the theoretical advantage of reduced interference with the ongoing task or mind-state. Rt-fMRI neurofeedback has demonstrated preliminary success in several areas, including training the brain to manipulate external computerized devices such as prostheses (deCharms, et al., 2004, Neuroimage 21(1):436-443; Birbaumer, et al., 2008, Current Opinion in Neurology 21(6):634-638), communicating with locked-in patients or those previously thought to be in vegetative states (Owen and Coleman, 2008, Nat Rev Neurosci 9(3):235-243; Monti, et al., 2010, N Engl J Med 362(7):579-589), lie detection (Spence, et al., 2004, Philos Trans R Soc Lond B Biol Sci 359(1451):1755-62; Langleben, et al., 2005, Human Brain Mapping 26(4):262-272), controlling symptoms of chronic pain (deCharms, et al., 2005, Proc Natl Acad Sci USA 102(51):18626-18631) and modulating brain activation in regions associated with particular cognitive states (Caria, et al., 2007, Neuroimage 35(3): 1238-1246; Caria et al, 2010, Biological Psychiatry 68(5):425-432; Hamilton et al., 2011, Human Brain Mapping 32(1):22-31). However, it has not been used as a tool for exploring the correlates between 1st person subjective experience and brain activity. Such a modality would be especially useful in investigating neural correlates of introspective states that are conceptually difficult to convey in the first-person. For example, during the practice of mindfulness meditation, individuals practice dropping into states of “bare awareness,” that, by definition, are free of all concepts including the concept of ‘someone’ paying attention (Gunaratana, H. (2002), Mindfulness in Plain English. Somerville, Mass., Wisdom Publications; Lutz, et al., 2008, Trends in Cognitive Sciences 12(4):163-169). Meditators can report being mindfully aware just after, but not during, moments of mindfulness because the act of observing disrupts the state itself. In extreme examples, such as absorptive concentration meditative states, awareness is described as “one-pointed” in the sense that conscious experience is so focused that it becomes literally a single point of focus (Buddhaghosa, A. (1991), The path of purification: Visuddhimagga, Buddhist Publication Society).
Therefore, there is a need in the art for rt-fMRI neurofeedback systems and methods to bridge the gap between subjective self-report, as individuals link their experience (including quality, such as depth) with neural activation in a time-precise manner, but with minimal interruption of their state from an external probe or other interference. The present invention satisfies this need.